- 90 Posts. Joined 3/2015
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My first build, help me please! reverse flow - Page 3
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I believe Dave may be along to confirm this, but my understanding is the height of the chimney should be measured from the top of the CC. Remember, you have to think of this as an air pump, you have to overcome the hot air moving down if your chimney is not on the top of the CC. The further down you put your chimney, the more important it is to have a chimney that can use draft to pull hot air down to where it can get out. Don't over think this, just try to wrap your head around the concept of making water run uphill, you need relative vacuum ie, differential pressure.
http://feldoncentral.com/bbqcalculator.html Read the notes under Chimney Size and look at the pictures, all of the chimneys are on top of the CC.
Cc cut. I am pretty happy with the fit but will probably end up using a gasket of some sort.
Making sure I have a 31 sq inch hole per my calculations (I've used more graph paper in the last two weeks than my entire life! It helps me visualize things.
I treated the instal of the firebox like a VW engine install. Jack it in place with the Jack.
All lined up perrrrfect!
Next was to start the base. Since I am one man show, my chain hoist worked perfect!
The RF plate could not have fit more perfect! It matches up with the firebox perfect!
Here is where I stand. Overall, I could not be happier. Everything is square and looks awesome. My welds aren't great but are getting much better. Next is to finalize the small odds and ends. Vent handles, FB door latches, wheels, etc.
Now I just pray my calculations are accurate!
33 gallon craftsman air compressor
FB - 14 x 14 x 16 tall (3/16" thick)
31 sq inches fb opening
31" area under rf plate and at end of rf plate
RF plate 13.75" wide
25" stack made from 3" OD (2.75" inside diam.)
9" of air inlets
Edited by busmania - 4/14/15 at 6:50pm
This is the only pic I have. The sausage and wings were great, the ribs just ok. My first official cook will be this weekend. Thinking chicken.
A few updates.
While this is the first side box smoker I have ever used, I am still learning exactly how these things should work. It seemed as though the smoke was building in the CC. When I opened the door it would be a spinning vortex of thick smoke. Sometimes I could get rid of this and burn "clean smoke" by taking the temps up to around 300-325. I want this thing to work optimally from 250-400. So I made a few adjustments.
First I fixed my exhaust stack. Based on advice I received on this forum, I think the elbow was affecting the flow.
My air intake holes didn't seem right either. My bottom vent was at the same level as the fire grate so I moved it to below the fire grate. I also angled the vent opening for a more precise tuning. I also moved the upper vent higher and skinnier again for more precise air tuning.
I have only used it once since the changes but it already seems better. I still think I have a huge learning curve to get over (again this being the only side firebox smoker I have ever used...I don't know how they are 'supposed' to react to changes/function).
QUESTION for those of you familiar with how these thigns work. I am still having trouble getting a "clean" smoke at low temps (250). I can keep the temps that low but the smoke just doesn't seem super clean. Does this mean my fire is too big? Since making the above changes, the fire seems to burn more efficient and I didn't need as much wood...but I still want a cleaner smoke at low temps. At 300 degrees and hotter it seems easy to get that clean smoke...but I want to smoke at lower temps. My thermometer is calibrated too.
Keep on smokin'
Edited by busmania - 8/5/15 at 9:42am
- 18,146 Posts. Joined 11/2010
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All air leaks are 100% sealed. I added a gasket and clamps to the CC door. FB to CC opening looks good and clear...so long as my math was correct originally.
Having learned smoking on a big green egg, I have learned to be patient with adjustments. It seems as though by the time the temp finally settles (after making a vent adjustment) and things look good with the clean smoke, I need to add more wood which makes it burn dirty again. I do heat them on top of the FB. I am thinking the wood I am adding needs to be a little thinner/smaller so it can burn instead of smolder at the lower temps. Should I have to constantly adjust the vents after adding wood or after the wood has burned for 30 minutes or so or once a good setting is found, should the vents remain largely untouched (on a perfectly good working smoker)?
Pipe is 2.75" inside diameter. About 30". I have thought about trying a 3.25" inside diameter but I am tired of working on it!
I will give that a try. My next smoke I am going to try and make a smaller fire, leave the upper vent almost all the way closed and use smaller pieces of wood. I also think I have been using too much upper vent.
Another question, should I be using any charcoal in addition to the hardwoods? When I started on this journey, I was hoping to only burn wood and not have to deal with charcoal...that's what the egg is for.